New record of an ectoparasitic isopod, Zonophryxus retrodens Richardson, 1903 (Crustacea: Dajidae) from Japan

Abstract

The ectoparasitic isopod, Zonophryxus retrodens Richardson, 1903, is recorded for the first time from Japan. This species is distinguished from other congeners mainly in the following combination of characters: elongate oval body, 5 dorsal traces of segmentations on pereon, 3 pairs of notches on lateral margins of anterior half of the body in female, broad ventral flange in female; and ovoid pleotelson without uropods in male. This study provides additional information on this species, including a description, host, coloration, and scanning electron micrographs.